Out of the following coordination entities,which is chiral (optically active)?

Which of the following complex ions exhibits geometrical isomerism?

Total number of isomers possible for the complex $[Co(en)_2Cl_2]$ is

Which of the following pairs of transition metal ions have the same calculated values of magnetic moment?

Arrange the following in the increasing order of the number of unpaired electrons present in the central metal ion:
$I.$ $[MnCl_6]^{3-}$
$II.$ $[FeF_6]^{3-}$
$III.$ $[Mn(CN)_6]^{3-}$
$IV.$ $[Fe(CN)_6]^{3-}$

The electronic configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Ni^{2+}$ ions are $3d^4, 3d^5, 3d^6$ and $3d^8$ respectively. Which of the following aqua complexes exhibits the minimum paramagnetic behavior?